Wide range friction welder

ABSTRACT

A friction welding machine is adapted to weld workpieces having a wide range of diameters by utilizing a unidirectional drive means, such as a one-way overrunning clutch, which is disposed between rotatable components of the machine and a rotatable workpiece holding spindle. The unidirectional drive means provides a driving connection between the rotatable components and the spindle when relative motion therebetween is in one direction and prevents a driving connection when relative motion therebetween is in an opposite direction. One embodiment of the invention has a dual-spindle arrangement in which the spindles may be operated independently or together to provide a machine which is capable of friction welding workpieces having a large range of diameters. The dual-spindle arrangement also permits workpieces of relatively large diameter to be loaded and unloaded from the machine while the input energy components of the machine are being accelerated to welding velocity.

United States Patent al1of,lll. 21 Appl.No. 19,291 22 Filed Apr. 25,1969 [45] Patented [73] Assignee Aug. 17, 1971 Caterpillar Tractor Co.Peoria, Ill.

[54] WIDE RANGE FRICTION WELDER 14 Claims, 1] Drawing Figs.

'[52] U.S. Cl 228/2,

I 29/4703, 156/73 [51] Int. Cl. B23k 27/00 [50] Field of Search 228/2'3,235,162 2/1966 Hollander 3,234,646 2/1966 Hollanderetal.

Primary Examiner-John F. Campbell Assistant ExaminerRobert J. CraigAttorney-Fryer, Tjensvold, Feix, Phillips & Lempio ABSTRACT: A frictionwelding machine is adapted to weld workpieces having a wide range ofdiameters by utilizing a unidirectional drive means, such as a one-wayoverrunning clutch, which is disposed between rotatable components ofthe machine and a rotatable workpiece holding spindle. Theunidirectional drive means provides a driving connection between therotatable components and the spindle when relative motion therebetweenis in one direction and prevents a driving connection when relativemotion therebetween is in an opposite direction. One embodiment of theinvention has a dual-spindle arrangement in which the spindles may beoperated independently or together to provide a machine which is capableof friction welding workpieces having a large range of diameters. Thedual-spindle arrangement also permits workpieces of relatively largediameter to be loaded and unloaded from the machine while the inputenergy components of the machine are being accelerated to weldingvelocity.

PAIENTEDAusmm: 3599857,

sum 1 OF 6 INVI'INTURQ CALVIN D. LOYD THEODORE L. OBERLE IRA H. SAGE BYRONALD L. SATZLER f 5? 9-; I 2074/ 7) ATTORNEYS PATENTED AUG] 7 I971SHEET 2 BF 6 TORS I m lwhmm MN owTw R1 m: a Q ,,,m%@% ms 31 3 .m lllli rmm @w w@ E. E @Q o e N: H mm m s ms m Name @2 v @m 3 3 INVEN CALVIN 0.LOYD THEODORE OBERLE IRA H. SAGE BY RONALD L. SATZLER J94 hal 9- Z AATTgRNEYS V PATENTEDAUGITIQH 3.599.857

SHEET 3 OF 6 78 I00 104 102 m 1 I06 I08 no INVENTORS CALVIN D. LOYDTHEODORE L. OBERLE IRA H. SAGE RONALD L. SATZLER YJ 7/ a g 9- l IATTORNEYS SATZLER INVENTORS CALVIN D. LOYD THEODORE L. OBERLE IRA H.SAGE RONALD L.

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sum s or 6 EL J 90 :34 H6 INVENTURS CALVIN D LOYD THEODORE l OBERLE IRAH. SAGE BY RONALD L. SATZLER ATTORNEYS WIDE RANGE FRICTION WELDERBACKGROUND OF THE INVENTION This invention relates to friction weldingof the general type wherein two workpieces are subjected to relativerotation while in rubbing contact with each other to generate frictionalheat to raise the workpieces to a suitable welding temperature,whereupon the relative rotation subsides and a bond is formed betweenthe workpieces.

It is also to be understood that the invention is applicable to theinertia friction welding process as described in U.S. Pat. No. 3,273,233and as set forth below.

In the inertia welding process the energy required to bring the commoninterface of the workpieces to a bondable condition is stored as kineticenergy in rotating inertia weights. These weights generally take theform of flywheels and are connected to one of the workpieces and theentire energy necessary to form the bond is stored in the weights priorto the engagement of the workpieces at the interface. The stored energyis discharged into the interface through frictional heating and plasticworking developed at the interface as the rubbing contact slows therotating weights and the bonding cycle is concluded.

More specifically, the present invention is directed to a wide rangefriction welding system which provides reliability and versatilitywhereby a wide variety of workpiece sizes may be welded with a minimalamount of downtime between welding operations.

One of the principal objects of the present invention is the provisionof a welding machine which has a unidirectional drive means, such as aone-way overrunning clutch, disposed between rotatable drive componentsof the machine and a rotatable workpiece holding spindle to permit thewelding of workpieces having a wide range of diameter sizes.

Another principal of the present invention is the provision of afriction welding machine having a dual-spindle arrangement in which thespindles may be operated independently or together to provide for thefriction welding of workpieces having a large range of diameters.

Another object of the invention is the provision of a dualspindlearrangement whereby workpieces may be loaded or unloaded from themachine while the input energy components of the machine are beingaccelerated for a succeeding welding operation.

A further object of the invention is the provision of a dual spindlearrangement and a selectively operable dual-flywheel arrangement wherebyeither a small or large amount of input energy may be supplied for thefriction welding of a wide range of workpiece sizes.

Still another object of the invention is the provision of a dual-spindlearrangement wherein the drive means for one of the spindles is providedwith a one-way overrunning clutch which clutch functions to connect ordisconnect a drive motor to the spindle depending upon the speed androtational direction of the drive motor.

Yet another object of the invention is the provision of a dual spindlefriction welder in combination with a one-way overrunning clutch and apair of selectively operable coupling elements to provide inter alia forthe following drive arrangements:

independent rotation of either spindle;

maintaining one spindle stationary for loading and unloading of weldpieces while the other spindle is being accelerated for a subsequentwelding operation;

coupling the two spindles directly to each other to utilize the combinedenergy stored in inertia components on either one or both spindles for afriction welding operation; and

utilizing only the energy of the workpiece spindle by causing theworkpiece spindle to rotate in a direction opposite the normal drivingdirection whereby the one-way clutch permits the outer spindle to remainat rest.

Other and further objects and advantages of the present invention willbe apparent from the following description and claims and areillustrated in the accompanying drawings which, by way of illustration,show preferred embodiments of the present invention and the principlesthereof and what are now considered to be the best modes contemplatedfor applying these principles. Other embodiments of the inventionembodying the same or equivalent principles may be used and structuralchanges may be made as desired by those skilled in the art withoutdeparting from the present invention and the purview of the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational viewillustrating one exemplary embodiment of a friction welding machineconstructed in accordance to the present invention;

' FIG. 2 is a longitudinal view, partially in section, illustratingcertain details of the dual spindle and flywheel arrangement of themachine illustrated in FIG. 1;

FIG. 3 is an end view taken at the front end of the machine;

FIG. 4 is an end view taken at the back end of the machine;

FIG. 5 is a longitudinal view, partially in section, illustratingcertain structural details of the driving components for the dualspindles arrangement of the present invention;

FIGS. 6-10 are diagrammatic view illustrating the power drive linethrough the machine during various phases of a friction weldingoperation; and,

FIG. 11 is a longitudinal view, partially in section, of a modifiedembodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a preferredembodiment of the invention comprises a frictional welding machine 20having a base or support assembly comprised of horizontal plates 22 and24.

The base assembly further comprises angle supports 26, 28 I and 30 whichcooperate with the horizontal plates 22 and 24 and two I-beams 32 and 34(see FIGS. 3 and 4) to provide a very rigid structure for supporting thevarious machine components. Mounted on the support structure justdescribed are tailstock assembly 38, a spindle housing assembly 40 and ahydrostatic transmission and drive assembly 44.

An electric motor 46 drives two hydraulic pumps 48 and 50 and the pump50 powers a hydrostatic motor 52. The pump 48 is utilized to power ahydraulic ram assembly as will be described in greater detail at a laterpoint in the description. As further shown in FIG. 1 a plurality offlywheels 54, 56 and 58 may be selectively connected to a flywheel hub60 for use in a given welding operation. The number of flywheels whichare connected to the flywheel hub 60 would of course depend upon thesize of the workpieces which are to be joined by the friction weldingoperation. Those flywheels which are not required for a given weldingoperation may be stored on a housing 62.

The spindle housing 40 is provid d with dual hydraulic rams 64 and 66which are powered by the pump 48 and have piston rods 68 and 70 whichextend through guide sleeves '7 2 and 74 provided on the tailstockassembly 38. The outermost ends of the piston rods 68 and 70 areattached to a tailstock brack t 76 by means of suitable nuts 78 and 80.The hydraulic rams 64; and 66 may be actuated to move the tailstockassembly 38 horizontally toward and away from the spindle housing 40.The hydraulic rams also serve to provide the necessary axial thrust orpressure required during a friction welding operation.

As also shown in FIG. 1 a workpiece 84 is firmly clamped in a rotatablechuck or fixture 86 which chuck is fastened to a workpiece spindle 88.As will be described in greater detail at a later point in thedescription, one or more flywheels 89 (see FIG. 2) may also be attachedto the spindle 88 depending upon the size of the workpieces beingwelded. A second workpiece 90 is clamped in a split fixture 92 whichensures that the second workpiece 90 will not rotate during a weldingoperation. The fixture 92 is fastened to the tailstock base 94. Itshould be understood that the tailstock fixture 92 could be anonrotatable chuck or any other suitable type of fixture which will holdthe workpiece 90 against rotation. The fixture 92 also has means (notshown) for vertical and horizontal adjustment. In addition, a backupmember 96 is fastened to and passes through the bracket 76 to backup theworkpiece 90. The backup member 96 is also adjustable to accommodateworkpieces of various length.

FIGS. 3 and 4 are end views taken from each end of the machine andillustrate how the spindle housing 40 and the tailstock assembly 38,including the bracket 76, are positioned at an angle of approximately 30to the horizontal base of the machine. This angled position of thetailstock assembly 38 and the spindle housing 40 provides easier loadingand unloading of the machine.

It may also be observed from FIG. 3 that the hydraulic pumps 48 and 50are connected directly to the output shaft of the electric motor 46. Thehydraulic pump 48 is provided with suitable hydraulic connections (notshown) for connecting the pump to the hydraulic rams 64 and 66. Inaddition, the hydrostatic motor 52 and the housing 62 are fastened toand supported by a bracket assembly 98.

FIG. 4 illustrates the tailstock end of the machine. As shown in FIG. 4,four sets of linear motion roller bearings 100, 102, 104 and 106 supportthe tailstock assembly 38 and provide means for relatively frictionlessmovement of the tailstock assembly in a horizontal direction. Thesebearings are in contact with and travel along machined ways of a plate108. A guide tongue 110 travels in a machined slot to help guide thetailstock assembly as it moves forwardly or backwardly.

FIG. 2 is a sectional view illustrating the internal components of thespindle assembly 40 and the drive assembly 44. The machine contains twoseparate spindles; the previously mentioned workpiece spindle 88 and asecondary spindle 116. The reason for the use of two spindles will beexplained at a later point in the description with respect to a typicalwelding operation.

A thrust bearing assembly 118 is also shown and is essentially comprisedof several individual angular contact ball bearings which are matchedand assembled to form one bearing. The thrust being is provided toabsorb axial thrust produced during a friction welding operation.

The secondary spindle 116 is fastened to the flywheel hub 60 by means ofcap screws 120. A bearing housing 122 is provided with spindle bearingelements 124 which support the secondary spindle 116 for rotation withinthe housing. The secondary spindle 116 is also fastened to a coupling128 by means of cap screws 130.

The coupling 128 is connected to the inner race 133 of a one-way spragclutch 134 by means ofa key 136 (see FIG. The outer race 135 of theone-way clutch 134 is fastened to a hollow drive shaft 138 by means ofcap screws 140. The hydrostatic motor 52 is connected at all times tothe drive shaft 138 by means ofa splined shaft 142.

A spindle shaft 144 has a first end 146 located near the end of thehydrostatic motor shaft 142. The spindle shaft 144 extends through theone-way clutch 134 and the secondary spindle 116 where the second end148 of the shaft is connected to the workpiece spindle 88 by means of asplined or other suitable connection as shown at 150.

As best shown in FIG. 5 a movable coupling 152 is situated between thehydrostatic motor shaft 142 and a splined end 154 located at the firstend 146 of the spindle shaft 144. The coupling 152 is connected to thedrive shaft 138 by external splines 156 and may also be connected to thesplined end 154 of the spindle shaft 144 by means ofinternal splines158. This latter connection between the splined end 154 of the spindleshaft 144 and the internal splines 158 of the coupling 152 occurs whenthe coupling is shifted to the right.

Thus, there exists a condition when the coupling 152 is connected toboth the spindle shaft 144 and the main drive shaft 138 which driveshaft is always connected to the hydrostatic motor 52. The lateralshifting of the coupling 152 may be accomplished through means of ahydraulic or air shift assembly 162 which actuates a lever 163 to move asleeve 164 which sleeve is connected to the coupling 152 by a pin 168.The drive shaft 138 is provided with slots 166 which allow the pin 168which is received in a bore 170 in the coupling 152 to shift thecoupling laterally into engagement with the splined end 154 ofthespindle shaft 144.

By utilizing coupling 152 and the properties of the one-way clutch 134,the workpiece spindle 88 can be driven in a direction opposite to thenormal driving direction without causing the secondary spindle 116 andthe related flywheels 54, 56 and 58 to rotate. Advantage of thisarrangement will be explained in the weld sequence description set forthat a later point in the description. In addition, another sleeve typecoupling 176 (see FIG. 2) is provided for connecting the secondaryspindle 116 to the workpiece spindle 88. Shifting of the coupling 176 isaccomplished through the use of a hydraulically or air operated shiftassembly, part of which is shown at 178. The entire spindle assembly 40is fastened to and supported by mounting brackets 180 and 182 which arefastened to the base plate 22.

FIGS. 6-10 illustrate in diagrammatic form various phases of operationof the friction welding machine of the present invention. In FIGS. 6-l0reference numerals have been used which correspond to those referencenumerals depicted in FIGS. 15. In addition, a power drive line isrepresented in FIGS. 6l0 by heavy dark lines having arrows.

Referring to FIG. 6, the motor 52 is shown turning the flywheels, showngenerally at 59, by means of the power drive 190 which drives throughthe main drive shaft 138, the oneway overrunning clutch 134 and thesecondary spindle 116. In FIG. 6 the coupling 152 and the coupling 176are not activated and consequently the workpiece spindle 88 does notrotate.

In FIG. 7, the motor 52 has been shut down and the flywheels 59 have ineffect been disconnected from the motor since the overrunning clutch 134permits the flywheels to continue rotating even though the motor isstopped. After the motor is stopped the coupling 152 is activated toconnect the workpiece spindle 88 to the motor 52 via spindle shaft 144.The workpiece spindle 88 is then accelerated by the motor and duringthis time the secondary spindle 116 and associated flywheels 59 continueto freewheel or coast.

Referring to FIG. 8 the workpiece spindle 88 has been accelerated by themotor 52 and as the spindle 88 reaches the same speed as thefreewheeling secondary spindle 116 and flywheels 59, the motor 52 willbegin driving the secondary spindle 116 by means of the overrunningclutch 152. In addition, the motor 52 continues to drive the workpiecespindle 88 via shaft 144. Thus, in the condition shown in FIG. 8 boththe workpiece spindle 88 and the secondary spindle 116, having theflywheels 59 connected thereto, are rotating at the same speed. At thisstage in the operation the coupling 176 may be activated to directlyconnect the flywheel spindle 116 and associated flywheels 59 to theworkpiece spindle 88. The motor 52 is then accelerated to bring thecoupled spindles up to the desired welding speed.

FIG. 9 illustrates the condition of the welding machine fter the weldingspeed has been reached. After the welding speed has been attained, thecoupling 152 is disconnected from the motor 52 and the motor may bestopped. Stopping of the motor 52 is effect disconnects the motor fromthe spindle 116 since the one-way clutch 134 is in an overrunningcondition. At this stage in the operation, the coupled assembly of thesecondary spindle I16 and the workpiece spindle 88 are in freewheelingor coasting condition at the desired welding speed and a friction weldmay be made by moving the tailstock assembly having the workpiece 90into contact with the rapidly rotating workpiece 84.

FIG. 10 illustrates a different mode of operating the friction weldingmachine of the present invention. In FIG. 10 the coupling 152 has beenactivated to connect the motor 52 to the workpiece spindle 88. However,the-motor 52 is powered in a reverse direction as compared to FIGS. 6-9which of course turns the workpiece spindle 88 in a reverse direction.Since the clutch 134 is a one-way clutch, it will not drive the flywheelspindle 116 when the motor 52 is powered in a reverse direction andtherefore the flywheels 59 remain stationary. Consequently, theworkpiece spindle 88 may be utilized, with or without flywheels, such asshown at 89 in FIG. 2.

This aspect of the machine operation permits the welding of small.diameter workpieces since the inertia mass associated with" the flywheelspindle 116 is not transmitted through the power drive line 190. It isalso possible to achieve the operating method shown in FIG. 10 bydisconnecting the coupling 128 rather than by turning the workpiecespindle 88 ina reverse direction. Disconnecting the coupling 128prevents rotary motion from being imparted to flywheel spindle 116 whichshould not rotate when operating the machine in the manner depicted inFIG. 10.

Atypical weldingsequence for welding two parts of considerable diameteror area would be conducted as follows. After calculation of the requiredamount of input energy needed, flywheels (such as the flywheels 54, 56and 58) having the correct size are attached to the flywheel hub 60. Thehydrostatic motor 52 is then accelerated by means of the electric motor46 and the hydrostatic pump 50.

The motor 52 turns the drive shaft 138 which drives the one-wayoverrunning clutch 134 which, in turn drives the secondary spindle 116and the attached flywheels. The workpiece spindle 88 has remained atrest during this time since neither the coupling 152 nor the coupling176 has been activated and consequently the spindle shaft 144 is notturning.

Thus, while the secondary spindle 116 and the flywheels associatedtherewith are being accelerated the workpieces 84 and 90 may be loadedandclamped into their respective workpiece holders. 5'

After the secondary spindle 116 attains a preselected velocity, thehydrostatic motor 52 is signalled to stop. However, the secondaryspindle 116 and the associated flywheels 54, 56 and 58 continue to coastor freewheel through the overrunning feature ofthe one-way clutch 134. Ig

After the motor 52 has been stopped, the coupling 152 is engaged bymeans of the hydraulic shifter assembly 162 which directly connects theworkpiece spindle 88 to the motor by means of the spindle shaft 144. Themotor 52 is again accelerated and at the moment when the speed of theworkpiece spindle 88 attains the speedof the freewheeling secondaryspindle 116 the one-way clutch again begins to drive the secondaryspindle 116. v

Both the workpiece spindle 88 and the secondary spindle 116 are nowbeing driven by the motor 52 and hence their velocity is identical.Since their velocity is the same, the coupling 176 may be activated bythe shifter assembly partially shown at 178 to directly connect thesecondary spindle 116 to the workpiece spindle 88. At this time thehydrostatic motor accelerates both spindles to a preselected weldingvelocity.

Once the welding velocity is reached the coupling 152 is disengaged andthe hydrostatic motor is signalled to stop. As the speed of thehydrostatic motor falls off to zero the overrunning feature of theone-way clutch 134 in effect disconnects the flywheel spindle 116 fromthe motor. At this time the entire coupled assembly is freely rotatingat the desired welding speed and the dual hydraulic rams 64 and 66 areactivated to move the tailstock assembly 38 toward the spindle housing40 and the workpieces 84 and 90 are forced into rubbing contact underthe desired axial thrust or pressure. As the workpieces are forced intocontact at their common interface frictional heat is generated-whichraises the workpiece interface to a suitable bonding temperaturewhereupon the relative rotation subsides as the workpieces become bondedto each other.

At the end of the weld cycle the coupling 176 is disengaged and thehydraulic rams 64 and 66 are actuated to move the after the coupling 176is disconnected.

tailstock assembly 38 into the preweld condition. The welded assemblymay now be removed from the machine and the weld cycle may be repeated.It should be understood that the secondary spindle 116 and associatedflywheels may be accelerated in preparation for another weldingoperation immediately .The provision of the dual-spindle arrangementpermits a decided advantage in that the secondary spindle 116 andassociated flywheels may be accelerated while the workpiece spindle 88remains at rest. In this manner the workpieces 84 and 90 may be loadedor unloaded while the large inertia mass associated with the secondaryspindle 116 is being accelerated to the desired high speed. This is aparticularly advantageous feature when welding operations are beingperformed on workpieces having large diameters and therefore requiring ahigh-input energy factor.

At the same time the dual spindle system incorporated in the instantmachine permits the welding of the workpieces having rather smalldiameters since it is possible to utilize only that energy which isgenerated through rotation of the workpiece spindle 88. As previouslypointed out, this latter mode of operation is accomplished by engagingthe coupling 152 and accelerating the hydrostatic motor 52 in adirection opposite to the normal driving direction. Under thesecircumstances the one-way clutch 134 freewheels and the flywheel spindle116 remains stationary as the workpiece spindle 88 is accelerated to thepreselected velocity. After the preselected velocity is attained thecoupling 152 is disconnected and the rams 64 and 66 are attached tobring the tailstock workpiece 90 into engagement with the rapidlyrotating workpiece 84 associated with the freewheeling workpiece spindle88.

The dual-spindle arrangement makes it convenient to alternately weldboth large'and small parts because when welding smaller parts theflywheels 54, 56 and 58.do not have to be removed from the hub 60 of thesecondary spindle 116 since the spindle 116 doesnot rotate when themotor rotates in a direction opposite the regular driving direction.

As previously noted the machine of the present invention has also beenprovided with a dual-flywheel arrangement. That is, in'addition to'theflywheels 54, 56 and 58 associated with the secondary spindle 116 one ormore flywheels, such as shown at 89, may also'be attached to theworkpiece spindle 88. This feature of the machine makes it possible tobridge the gap of energies available from rotating the workpiece spindle88 alone as compared with rotation of the workpiece spindle 88 whencoupled with the secondary spindle 116 and the inertia mass associatedtherewith. Even with no flywheels attached to the hub 60 the energyprovided by rotation of the secondary spindle 116 is quite large andwould result in too much energy for the successful friction welding ofintermediate sized workpieces. However, since flywheels may be attachedto the workpiece spindle 88 the necessary energy for weldingintermediate sized workpieces can be provided by the machine.

FIG. 11 illustrates another embodiment of the invention wherein aunidirectional drive means, such as a one-way overrunning clutch, isutilized to provide for the welding of a wide range of workpiecediameters. In FIG. 11, a friction welding machine spindle assembly isgenerally shown at 200. The s indle assembly 200 comprises a spindlehousing 203 which contains a power drive shaft 205, a unidirectionaldrive assembly generally shown at 213 and a main workpiece holdingspindle 233.

The power drive shaft 205 is supported for rotation within a drive shafthousing 207. A suitable bearing assembly 209 supports the drive shaft205 for rotation within the drive shaft housing 207. Although not shown,the power shaft 205 is connected to a transmission and motor means whichimpart rotation to the drive shaft during a welding operation. A flangeelement 211 is formed on one end of the power drive shaft 205.

An outside race 215 of the one-way overrunning clutch assembly 213 isfastened to the flange 211 by means of suitable bolts 217 or the like.The one-way overrunning clutch 213 is preferably a sprag clutch and hasan inner race 219 which is connected to a clutch output shaft 221 bymeans of a splined connection 223.

Sprag elements 225 are located between the outer race 215 and the innerrace 219 in a manner such that when the outer race is rotated in onedirection the sprag elements 225 will wedge between the inner and outerraces and impart rotation from the outer race to the inner race.Conversely, when the outer race 215 is rotated in the opposite directionthe sprag elements 225 do not wedge between the inner and outer racesand there is no driving connection between the outer race to the innerrace. Two ball bearing assemblies 227 and 229 are positioned between theouter race 215 and inner race 219 to provide for relative rotationbetween the inner and outer race elements when the clutch 213 overruns.

The clutch output shaft 221 extends through a hydrostatic bearing thrustblock 231 and is fastened to the main workpiece spindle 233 by means ofcap screws (not shown) which extend through the flanged portion 222 ofthe clutch output shaft 221. Bearing assemblies 235 and 237 support themain workpiece spindle 233 for rotation within the housing 203. Theouter end of the workpiece spindle 233 is provided with a workpieceholding chuck 240 which has gripping means for firmly holding aworkpiece 242. One or more flywheels such as shown at 244 and 246 may beattached to the chuck 240 depending upon the size of the workpiecesbeing welded.

During a welding operation the power drive shaft 205 is rotated by themotor and transmission (not shown). The power drive shaft 205 in turnrotates the outer race 215 of the one-way overrunning clutch 213. Theouter race 215 imparts rotation to the inner race 219 of the clutch bymeans of the sprag element 225. Since the inner race 219 of the clutchis splined to the clutch output shaft 221 the clutch output shaft alsorotates and causes rotation ofthe main workpiece holding spindle 233.

After the main spindle 233 has been rotated to a predetermined velocitythe motor means is stopped which thereby stops rotation ofthe powerdrive shaft 205 and the outer race 215 of the clutch assembly 213. Thesprag elements 225 will then release and the inner race 219 of theclutch will overrun or continue to rotate as will the clutch outputshaft 221 and the main spindle 233. The weld can then be made withoutthe motor, transmission, power drive shaft 205 and outer clutch race 215adding energy to the welding mass. In other words, because of theone-way overrunning clutch 213 is located relatively close to therotatable workpiece 242 it is possible to weld small workpieces becausethe inertia or rotating mass of most of the drive line components may bedisconnected from the workpiece spindle during the actual weldingoperation. On the other hand, relatively large workpieces may also bewelded on the machine embodiment shown in FIG. 11 since a considerableamount of flywheel mass may be attached to the chuck 240.

In general, the embodiment of the invention shown in FIG. 11 differsfrom the previously described dual spindle arrangement in that it may beused to weld a wide range of workpiece diameters including quite smallworkpieces which require very little inertia mass.

While we have illustrated and described preferred embodiments of ourinvention, it is to be understood that these are capable of variationand modification, and we therefore do not wish to be limited to theprecise details set forth, but desire to avail ourselves of such changesand alterations as fall within the purview of the following claims.

We claim:

1. In a friction welding machine for joining a first workpiece to asecond workpiece by means of relatively rotating the workpieces andforcing them into contact at a common interface to generate frictionalheat to raise the workpieces to a suitable bonding temperature whereuponthe relative rotation subsides and the workpieces become bonded to eachother, the improvement comprising: a motor; a drive shaft connected tothe motor; a first spindle connected to the drive shaft by means of aone-way overrunning clutch; said one-way clutch having a connection withthe drive shaft so that rotation of the drive shaft in a first directionproduces rotation of the first spindle while rotation of the drive shaftin a second direction has no effect on the first spindle; means foroperatively connecting inertia mass to the first spindle;

a second spindle having workpiece holding means associated therewith;and

first coupling means operable to selectively couple the second spindleto the drive shaft so that the second spindle may be rotated in onedirection without effecting rotation of the first spindle.

2. A friction welding machine as set forth in claim 1 and furthercomprising second coupling means operable to selectively couple thefirst spindle to the second spindle.

3. A friction welding machine as set forth in claim 1 wherein the secondspindle has means for operatively connecting inertia mass thereto.

4. A friction welding machine as set forth in claim 2 wherein the secondspindle has means for operatively connecting inertia mass thereto.

5. A friction welding machine as set forth in claim 1 wherein the firstspindle and the second spindle are axially aligned and a portion of thefirst coupling means extends through the first spindle and is mountedfor relative rotation with respect to the first spindle.

6. A friction welding machine as set forth in claim 5 and furthercomprising second coupling means operable to selectively couple thefirst spindle to the second spindle.

7. A friction welding machine as set forth in claim 5 wherein the secondspindle has means for operatively connecting inertia mass thereto.

8. A friction welding machine as set forth in claim 6 wherein the secondspindle has means for operatively connecting inertia mass thereto.

9. A method of friction welding a first workpiece to a second workpiececomprising placing a first workpiece in a workpiece holder associatedwith a first rotatable spindle; placing a second workpiece in anonrotatable workpiece holding device; rotating a second spindle havinga relatively large inertia mass associated therewith to a predeterminedspeed; rotating the first spindle having the first workpiece heldthereon until the first spindle attains the speed of the second spindle;interconnecting the first and second spindles after the first spindleattains the speed of the second spindle so that they rotate together;and, forcing the workpieces together to produce frictional heat at theircommon interface until a friction welded bond is formed as the energy isexpended from the inertia mass and the relative rotation ceases.

10. In a friction welding machine for joining a first workpiece to asecond workpiece by means of relatively rotating the workpieces andforcing them into contact at a common interface to generate frictionalheat to raise the workpieces to a suitable bonding temperature whereuponthe relative rotation subsides and the workpieces be ame bonded to eachother, the improvement comprising:

a drive motor;

a rotary spindle having workpiece holding means associated therewith;

rotatable means located between the drive motor and the rotary spindle;

unidirectional drive means disposed between the rotatable means and therotary spindle;

said unidirectional drive means operable for relative driving connectionbetween the rotatable means and the rotary spindle when the relativemotion therebetween is in one direction; and,

said unidirectional drive means further operable to prevent relativedriving connection between the rotatable means and the rotary spindlewhen the relative motion therebetween is in an opposite direction.

11. A friction welding machine as set forth in claim 10 wherein saidunidirectional drive means comprises a one-way overrunning clutch.

12. A friction welding machine as set forth in claim 11 and furthercomprising means for operably connecting inertia mass to the rotaryspindle.

14. A friction welding machine as set forth in claim 13 wherein theone-way overrunning clutch is disposed adjacent to the rotary spindle tominimize the inertiacomponents of the drive train during a weldingoperation.

1. In a friction welding machine for joining a first workpiece to asecond workpiece by means of relatively rotating the workpieces andforcing them into contact at a common interface to generate frictionalheat to raise the workpieces to a suitable bonding temperature whereuponthe relative rotation subsides and the workpieces become bonded to eachother, the improvement comprising: a motor; a drive shaft connected tothe motor; a first spindle connected to the drive shaft by means of aone-way overrunning clutch; said one-way clutch having a connection withthe drive shaft so that rotation of the drive shaft in a first directionproduces rotation of the first spindle while rotation of the drive shaftin a second direction has no effect on the first spindle; means foroperatively connecting inertia mass to the first spindle; a secondspindle having workpiece holding means associated therewith; and firstcoupling means operable to selectively couple the second spindle to thedrive shaft so that the second spindle may be rotated in one directionwithout effecting rotation of the first spindle.
 2. A friction weldingmachine as set forth in claim 1 and further comprising second couplingmeans operable to selectively couple the first spindle to the secondspindle.
 3. A friction welding machine as set forth in claim 1 whereinthe second spindle has means for operatively connecting inertia massthereto.
 4. A friction welding machine as set forth in claim 2 whereinthe second spindle has means for operatively connecting inertia massthereto.
 5. A friction welding machine as set forth in claim 1 whereinthe first spindle and the second spindle are axially aligned and aportion of the first coupling means extends through the first spindleand is mounted for relative rotation with respect to the first spindle.6. A friction welding machine as set forth in claim 5 and furthercomprising second coupling means operable to selectively couple thefirst spindle to the second spindle.
 7. A friction welding machine asset forth in claim 5 wherein the second spindle has means foroperatively connecting inertia mass thereto.
 8. A friction weldingmachine as set forth in claim 6 wherein the second spindle has means foroperatively connecting inertia mass thereto.
 9. A method of frictionwelding a first workpiece to a second workpiece comprising placing afirst workpiece in a workpiece holder associated with a first rotatablespindle; placing a second workpiece in a nonrotatable workpiece holdingdevice; rotating a second spindle having a relatively large inertia massassociated therewith to a predetermined speed; rotating the firstspindle having the first workpiece held thereon until the first spindleattains the speed of the second spindle; interconnecting the first andsecond spindles after the first spindle attains the speed of the secondspindle so that they rotate together; and, forcing the workpiecestogether to produce frictional heat at their common interface until afriction welded bond is formed as the energy is expended from theinertia mass and the relative rotation ceases.
 10. In a friction weldingmachine for joining a first workpiece to a second workpiece by means ofrelatively rotating the workpieces and forcing them into contact at acommon interface to generate frictional heat to raise the workpieces toa suitable bonding temperature whereupon the relative rotation subsidesand the workpieces become bonded to each other, the improvementcomprising: a drive motor; a rotary spindle having workpiece holdingmeans associated therewith; rotatable means located between the drivemotor and the rotary spindle; unidirectional drive means disposedbetween the rotatable means and the rotary spindle; said unidirectionaldrive means operable for relative driving connection between therotatable means and the rotary spindle when the relative motiontherebetween is in one direction; and, said unidirectional drive meansfurther operable to prevent relative driving connection between therotatable means and the rotary spindle when the relative motiontherebetween is in an opposite direction.
 11. A friction welding machineas set forth in claim 10 wherein said unidirectional drive meanscomprises a one-way overrunning clutch.
 12. A friction welding machineas set forth in claim 11 and further comprising means for operablyconnecting inertia mass to the rotary spindle.
 13. A friction weldingmachine as set forth in claim 11 and further comprising means foroperatively connecting inertia mass to the rotary spindle.
 14. Afriction welding machine as set forth in claim 13 wherein the one-wayoverrunning clutch is disposed adjacent to the rotary spindle tominimize the inertia components of the drive train during a weldingoperation.